DIYer’s Guide To Sealing Baseboards: Stop Drafts in 6 Steps

Remove old caulk

If your baseboards are caulked and the caulk has dried up and failed, it is essential to remove the old caulk before re-caulking the gap between the top of the baseboard and the wall. Depending on the caulks makeup and condition, this can be a headache of a process. For our situation, it was easiest to just remove the baseboard and clean the surface of both the wall and the back of the baseboard of old caulk using a putty knife.

Here’s how to get the baseboard off the wall. First, score the seam with a knife to facilitate easier removal of the baseboard. Start at one end of the baseboard piece and use a hammer to drive the trim puller into the gap between the wall and the baseboard. Move along the baseboard until it separates completely from the wall.

Remove any old nails from the baseboard with pliers before reattaching it to the wall. To reattach the baseboard, use a nail gun with 18-gauge Brad nails. Be sure to nail it to the studs or the bottom plate of the wall.

No quarter round?

Our drafty baseboard already had quarter-round molding installed on it from when we installed the new flooring. If you don’t have quarter-round or shoe molding, this can be the sole cause of drafty baseboards. Add it, and insert backer rod before installing the quarter-round if there are any gaps between the bottom of the baseboard and the floor.

Mask off drafty seams

Apply painters’ tape along the seams we’re sealing to keep your caulk beads in check and minimize painting touch-ups later on in the project.

Our focus is on two seams: the seam between the top edge of the baseboard and the wall, and the seam between the top edge of the quarter round and the face of the baseboard. Tape along the floor as well if you do not want caulk or paint on it, especially if it’s carpet.

Caulk the seams

Cut the tip of the caulk at a 45-degree angle for a smooth, controlled application. Start caulking the trim in a corner. Apply a thin bead of caulk to the gap between the top edge of the baseboard and the wall. If your trim is painted, apply a bead of caulk to the seam between the top edge of the quarter-round and the baseboard as well.  Use your finger to smooth out the bead of caulk and wipe away any excess with a damp rag.

Peel off the tape

While the caulk is still wet, peel the tape off. Clean up excess caulk with a wet rag before it dries. For the leftover caulk in the tube, cover the tip with tape or a caulk cap.

Fill and paint

If you removed and reinstalled your baseboard, fill your nail holes with wood filler to hide them. Then, lightly sand the holes smooth with 220-grit sandpaper. Clean up the dust afterwards to make sure everything is ready for painting.

Touch up the nail holes with paint while the caulk dries. After the caulk has dried, touch up the paint over the baseboard. You may need to re-mask off the areas you don’t want to paint before touching up.

There you have it! A finished, sealed baseboard that will save you money and keep your home cozy all through the year.

FAQ

Is it better to use caulk or wood filler to seal baseboard drafts?

Caulk is better for sealing baseboard drafts because it remains flexible and can accommodate the natural movement between the baseboards and the walls.

What is the best caulk for trim boards?

I found that the best caulk to use is acrylic latex or siliconized acrylic caulk, as they are flexible, durable, and easier to clean up.

Should a quarter-round be caulked?

Yes, all quarter-rounds should be caulked. Not caulking can let dust, pests, and drafts into your home.